Inverted bottle type water dispensers, commonly known as "water-coolers" or "water-stands," are often found in American homes and workplaces. They provide a source of pure drinking water in areas where the hygienic quality or the esthetic taste of the domestic water is otherwise questionable. They also provide a convenient way of cooling and/or heating the water before it is dispensed. These water-stands normally require the purified drinking water to be supplied from a source outside the home or workplace, such as the delivery of the bottled water from a supplier of bottled pure water or purchasing purified water from a vending machine.
These options can be expensive and/or inconvenient for the consumer. An attractive option for consumers is to fill the bottle directly from a household tap and filtering the water at the water-stand to provide a source of purified water suitable for drinking. This option provides a source of purified drinking water segregated from the tap water; tap water can then be used advantageously in applications where taste is of no concern, such as cleaning.
However, from time to time, the water-stand's filter needs to be replaced or disinfected due to the growth of microorganisms inside the filter. Thus, the filter should be easily installed, removed and disinfected and it is preferable that the consumer can install, remove and disinfect it himself or herself with relative ease. Further, it is preferable, from the consumer's standpoint, that the periods between disinfecting be reasonably long.
One method of extending the period between filter cleaning is to fashion the filter so that the flow of water through the filter flushes all the water previously standing in the filter and to allow convection currents to flow between the filter and reservoir. Also, if the water is heated or cooled in the reservoir, since this heating or cooling retards the growth of microorganisms, a filter which is substantially immersed in this water has its microbiological growth hindered.
It is also advantageous to the consumer that the filter be relatively inexpensive and universally adaptable to most conventional inverted bottle type water dispensers. Further, in view of water shortages being experienced in certain sections of the country, the design of the filter should provide, insofar as practical, that all the system's water be filtered and used.
Moreover, if heating or cooling systems are utilized in the water stand, scale accumulates on the heating or cooling elements, when hard water is heated or cooled, reducing the element's efficiency. Hardness also imparts an unpleasant taste to the water, especially when it is used in making coffee or tea and hardness interferes with the clarity of ice if the hard water is frozen. Thus, a superior filter used in a water-stand will soften the water as well as reduce harmful bacteria growth and remove or reduce other detrimental solutes.
Lead, zinc, copper, calcium, calcium bicarbonate, ammonia, sodium sulfite and hydrogen sulfide are examples of other detrimental solutes commonly found in tap water in the United States. Each, in sufficient quantities, is harmful if ingested or provides an unpleasant flavor to water. Accordingly, a filter, used to purify tap water in a water-stand, should remove these substances as well. Tap water in most areas of the country contains chlorines. Chlorines impart to water an unpleasant taste, especially when that water is subsequently used to make coffee. Consequently, in a system which filters tap water in an inverted bottle type water dispenser to supply purified water, chlorines should be removed as well.
Adding to the burden of prerequisites for a satisfactory filter for use in a conventional inverted bottle type water dispenser is the requirement that the filter does not significantly hinder the flow-rate of water into the reservoir from the bottle. For example, an average water cooler has a reservoir capacity of four thousand cubic centimeters. In an office of twenty-seven people with each drawing a five-ounce cup of water at a rate of ten seconds per person, this reservoir could potentially be drained in about four and one-half minutes. Therefore, it is necessary for the filter to provide for a flow-rate to the reservoir to exceed this demand.
There are many devices and methods for filtering water in an inverted bottle type water dispenser which have been disclosed. None, to the inventor's knowledge, provides a satisfactory solution to the problem, in light of the aforementioned requirements. The following cites and briefly describes a few of these devices and how they requite the imperatives indicated above.
Frank Senyal discloses an apparatus for filtering water in his U.S. Patent entitled, "Filter and Water Purifier" which issued Nov. 30, 1943 as U.S. Pat. No. 2,335,458. Here, Mr. Senyal provides a filter for a water cooler comprised of two receptacles connected in a nested, superposed relation. The first receptacle receives the neck and mouth of the inverted bottle (which is fitted with a feed tube/stopper arrangement) and utilizes a valve to direct the water flowing from a receiver to a first filter sandwiched between two screens. The water is then drained via a tube to the bottom of a second receptacle which provides for an upward flow of the water through second filter, thereupon to discharge into the water cooler's reservoir. The filter arrangement depends into the reservoir of the water cooler by an outwardly extending flange resting on the recess of the reservoir.
Mr. Senyal discloses a further water purifier for a water cooler in U.S. Pat. No. 2,372,340, issued Mar. 27, 1945 and also entitled, "Filter and Water Purifier." In this disclosure, a strainer is attached to the feed tube/stopper arrangement and water is directed to flow from this strainer to a receiver. The receiver depends into the reservoir of the water cooler and is attached to the water cooler by means of screws. Via a valve, water drains from the receiver to a filter element which provides an upward flow of the water through the filter to discharge into the reservoir. The filter element is supported on the base of the reservoir and fits, sleeve-like, over the receiver.
Both these filter arrangements have disadvantages. For example, in the former patent, Senyal discloses a unified two filter arrangement which is awkward, at best, for the consumer to install or replace. In the latter patent, the filter arrangement comprises several distinct and unconnected parts which provides unwelcome complexity to the consumer. Moreover, because in both patents the bottom section is disclosed to drain the water from its top, water below the discharge ports will be retained, therefore removing the bottom section from the reservoir requires undue effort on the part of the consumer and, further, requires that this section be drained before disinfecting. Still further, Senyal teaches in both patents that the water below the ports is pushed into the reservoir by the preceding water. Therefore when there is no longer any preceding water (i.e.--the bottle is empty), the water below the ports within the filter is substantially lost for drinking. Additionally, Senyal's relatively convoluted flow-path of water--from the bottle to a cylindrical receiver (via a strainer in the second patent), then through a valve aperture offset to a side of the bottom of the cylindrical receiver, next through a first stage filter (in the first patent), down a tube to the bottom of a second stage filter and up through the second stage filter to a discharge port on top--is inconsistent with and unappreciative of the need to provide complete flushing of the filter and to permit the occurrence of convectional currents between the filter and the reservoir. Yet further, all the water in Senyal's receiver is not necessarily flushed out by the entry of more water from the bottle, especially if there are irregularities or indentations in the sides or bottom of the cylindrical receiver.
U.S. Pat. No. 4, 145,291 which issued Mar. 20, 1979 to Console et al., entitled "Disinfecting Means Within a Water Dispenser," discloses a conical basket supported by a flange interposed between the lower end of an inverted bottle and the upper end of the container of the water dispenser. The basket is disposed inside a reservoir of the water dispenser, directly below the mouth of the inverted bottle, and contains a vented, porous capsule containing silver for the inhibition of the growth of bacteria and other microorganisms in the water.
Console et al. do not otherwise address filtering the water for particulate or other harmful solutes and, in fact, provide a vent which would allow particulates or other harmful solutes to be introduced into the reservoir. Further, although silver ions are known to have a disinfecting effect in water, silver can be relatively expensive and its presence in drinking water is not desirable.
Carl Frahm discloses in U.S. Pat. No. 4,181,243, which issued on Jan. 1, 1980 entitled "Device for Filtering Beverages," a filter element provided at the inlet of a spigot for dispensing liquids from a reservoir.
As shown, Frahm's filter assembly requires the draining of the reservoir for its installation, removal or cleaning and is, therefore, relatively inconvenient and wasteful.
"Bottle and Filter" (U.S. Pat. No. 5,139,666, issued Aug. 18, 1992 to Charbonneau at al.) discloses an unusual inverted bottle which is refilled via a refill neck with a counter-cap which records the number of times the bottle is refilled. A filter is retained inside a discharge neck. The filter element is attached to the bottle via screw-on cap and held in place by projections integral with the bottle. An air vent is provided near the filter element on the cap.
Charbonneau at al.'s invention requires a water bottle of an unusual design and a relatively complex attachment of the filter element to the bottle. Further, several pockets of water are likely to collect in the bottle which would be difficult to retrieve.
Heinrich Niewig discloses in U.S. Pat. No. 5,238,559, entitled "Filter Device," that issued Aug. 24, 1993, a filter device similar to that disclosed by Charbonneau et at. Unlike Charbonneau et at., Niewig provides a vent at the "refill" neck. Niewig's disclosure again requires a water bottle of unusual design and a relatively complex attachment of the filter element to the bottle very similar to Charbonneau et al.'s teachings on these points and, thus, Niewig shares Charbonneau at al.'s disadvantages.
In U.S. Pat. No. 5,441,179, titled "Ultra-Violet Disinfecting Device Adapted for Use with Bottled Water Dispenser" and issued on Aug. 15, 1995, Stephen Marsh discloses using ultraviolet light to eliminate biological growth in the reservoir of a water cooler.
Marsh provides an example of direction of the art toward complexity and expense. Also, Marsh provides no teachings on the removal of other harmful contaminants in the water.
Disclosed in U.S. Pat. No. 5,486,285 by Brian Feeney, "Air Met Valve for Water Cooler" (issued Jan. 23, 1996), is a filter system removably connected to the neck of a bottle of a water cooler and forming a watertight seal therewith. This system comprises a one way valve for admitting air into the bottle and a sleeve for receiving a replaceable water filter.
Feeney's design is also relatively complex. It also requires a threaded neck on the bottle to fit the threads of its filter system and is therefore specific to bottles with threaded neck, not unlike Charbonneau at al. and Niewig.
From the foregoing, it may be appreciated that there is a need for a water filter for an inverted bottle type water dispenser which is easily installed and removed, of relatively simple and inexpensive design, easily cleaned and disinfected, unwasteful of water, universally adaptable to most bottles used for inverted bottle type water dispensers, and with the dispensers as such, and filters dissolved oxygen and other dissolved gases and impurities such as lead to improve the taste and healthfulness of the water as well as softening water improving its taste and preventing scaling of heating or cooling coils in the dispenser.